1. Field of the Invention
The present invention generally relates to semiconductor lasers and integrated circuits. More specifically, the present invention relates to structures and methods for adjusting the wavelength of a laser via temperature control.
2. Related Art
Optical communication techniques offer high-bandwidth communication over long distances. Advantages over electrical cabling include exceptionally-low data-loss rates that allow long distances between amplifiers, high data-carrying capacity, and no crosstalk between fiber cables. However, since electrical VLSI circuits are typically used for processing information, using optical interconnects typically involves performing electrical-to-optical and optical-to-electrical conversion operations. Techniques for delivering data to optical components and breaking conversion bottlenecks become important, particularly if the photonics and electronics are not tightly-integrated.
Electrical bottlenecks between optoelectronic driver/receiver circuits and photonic devices have led to the development of mechanisms that facilitate tight integration between optics and electronics on VLSI circuits. However, a second bandwidth-density bottleneck arises in the optical interface when each fiber carries a single channel of data, and a large number of fibers carrying high-speed data channels need to be coupled to a given optoelectronic integrated circuit.
Different methods for multiplexing multiple channels into a single optical fiber exist, such as wavelength-division multiplexing (WDM), which allows each fiber to communicate multiple channels of information simultaneously. WDM overcomes fiber congestion problems and reduces the number of fibers that need to access a module, which simplifies connection and miniaturization efforts. However, fabricating and integrating a set of precisely-tuned lasers with appropriately-spaced wavelengths into a package solution for dense WDM remains challenging and costly in typical manufacturing processes, because of the fine tolerances involved in densely-integrating a set of laser signals into the thermal environment of a chip.
Hence, what is needed are structures and methods for enabling dense WDM without the above-described problems.